The invention relates generally to solar energy methods and systems, and particularly with systems and methods for solar energy distillation.
Solar energy is a free renewable energy source that is readily available in many parts of the world. Given that solar energy is readily available to all for merely the cost of equipment to convert it to an intended purpose, solar energy may be particularly attractive for use in areas with populations that have limited financial resources. Technological developments have resulted in the use of solar energy for many applications, for example, thermal heating systems, electricity production systems, and solar distillation systems.
Solar distillation systems (also referred to herein as xe2x80x9csolar distillers,xe2x80x9d xe2x80x9csolar stills,xe2x80x9d xe2x80x9csingle basin or multiple effect stills,xe2x80x9d or simply xe2x80x9cstillsxe2x80x9d) have been in use since 1872. Some examples may be found with reference to various patents including: U.S. Pat. Nos. 5,628,879; 4,135,985; 4,141,798; 4,487,659; and 4,267,021. Unfortunately, many of these prior art still designs suffer from various deficiencies so that they do not provide a practical solution for providing clean and safe drinking water to the masses of people throughout the world who have limited knowledge about solar energy distillation systems and finances. For example, many of the known stills are difficult and/or expensive to construct or purchase. In fact, in some areas of the world proper and safe building materials for building stills are not available. Some stills are often difficult to construct, difficult to move, not durable, and/or difficult to maintain.
One particular application of solar distillation systems is water distillation. In many geographical locations of the world clean and safe potable drinking water is expensive and/or in scarce supply. Often the available water supply is salty, brackish, and/or contaminated with various undesirable and possibly toxic substances which results in water that may not be suitable for human and/or animal consumption. These geographical locations are often remote and might not have common utilities such as electricity and/or effective public water purification systems. Further, the people who inhabit these locations may not have enough money to be able to afford public water or continuous electric utility cost. As a result they often resort to purchasing bottle water for drinking and cooking purposes. However, a properly designed and operated solar still as provided by the present invention may be a preferred alternative to purchasing bottled water by providing many years of clean safe good tasting water production to these people. Such a solar still may be extremely effective in providing clean drinking water from a high dissolved salt and other mineral content water, effective at eliminating dangerous bacteria such as cholera, E. coli, etc, cost effective, easy to install, and easy to maintain. Although many solar still designs are not always capable of effectively removing volatile organic compounds (VOC) such as pesticides, or petroleum distillates.
In one type of solar still the still basin may be sealed with a variety of materials, including silicone, so as to retain the liquid solution to be distilled. The basin sealing materials are applied to a rigid basin structural material or insulation material as a coating of material in liquid form that dries and adheres to a rigid basin structural material so as to seal the basin for retaining, for example, water. For example, the solar still basin structural material may be a cement, concrete or wood material and one or more layers of silicon may be manually spread over the surface of the basin or an insulation lined basin to seal the basin structural material from the liquid (e.g., water) to be distilled. This sealing layer(s) may be referred to as the xe2x80x9cmembranexe2x80x9d or xe2x80x9cdiaphragmxe2x80x9d of the still. However, manual application of the silicon is a cumbersome process and it is difficult to ensure an adequate seal in all locations of the basin due to the inaccuracy of the manual spreading process. Fumes from the silicon application can be toxic and cause people to become faint or nauseated. Further, some types of silicon used may break down and contaminate the water, resulting in contaminated distillate.
The present invention is directed to an improved solar powered distillation system and method that can be provided, cost effectively, to the masses of people worldwide. The improved solar powered distillation system may be made of lightweight, cost effective, and durable materials (e.g., aluminum) and construction to ensure a low cost still that is easily transportable (moveable), affordable and durable so as to provide years of safe clean water production for people at any location throughout the world. The solar powered still may have a waterproof membrane that is extruded, molded, and/or spray-on and installed in a lightweight basin as a liner for improved ease of still manufacturing and assembly as well as improved sealing. Further, the membrane may include silicone. In a preferred embodiment, the membrane material may be an opaque food grade non-toxic odorless, tasteless silicon, for example, Dow Corning 40/Silicone FDA Ingredients per CFR 177.2600. In one variation, the solar still basin may be formed from an aluminum sided insulation material, for example, Thermax made by Celotex. In another variation the solar still may also include a carbon filter attached to either the input or output of the solar still for filtering out VOCs. In a further variation the solar still may include adjustable legs to facilitate leveling the still to ensure the most efficient operation possible. In one preferred application, the solar still may be used as a solar water purification system and method. The still may be provided to users in kit form and assembled on location where it is to be used. In any case, the still is a portable cost effective system that may be used to provide distilled water in any location throughout the world.